Effectively positioning a ladder against a utility pole or other vertical structure has long been a safety concern. Ladders are a leading cause of fall-related fatalities and other serious injuries. Ladder inclination is the angle of the ladder from the horizontal. If the ladder inclination is too steep, the risk of injury is increased because the ladder is more likely to fall backward under load. If the ladder inclination is not steep enough, the risk that the ladder will slide out from under the ladder user increases.
To ensure that a ladder may be ascended safely, the ladder should be placed at an angle of approximately 75° from the horizontal. When positioning a ladder, it is difficult to determine quickly and with certainty that the angle is correct. Various types of ladder inclination indicators have been developed to show that the angle of the ladder is correct. However, most of these devices allow for a range of safe angles, or else provide no way to be certain that the device is operating correctly.
Consequently, among other needs, a need exists for an apparatus that may be used to show that a ladder is at a safe inclination.